Thomas Liquid Pump Technologies for OEM Applications

Diaphragm, Linear and Peristaltic Pumps

Pump engineering is a part of the Thomas DNA. Our liquid pumps are manufactured to the highest quality that sets the standard in the industry. Our pumps are well-suited to transfer any types of liquid, whether neutral or corrosive. They are compact by design, and are highly resistant to chemicals providing long life and maximal performance.

As a result of a fruitful collaboration between our engineers and our OEM clients, we are able to value-engineer and guarantee that our products are built to last.

Liquid Pump Technologies

Depending on the specifications, you can choose from liquid diaphragm pumps, peristaltic pumps or linear pumps. These pump types use positive displacement pump technologies and operate oil-free, and they can be mounted in virtually any position. The majority of our liquid pumps are maintenance-free. When it comes to our peristaltic pumps, they provide easy access for easy tubing replacement.

Because the selection of the right pump can determine the scale of success of the final solution, our product specialists and engineers are here to support you with each step of the selection process. Our experts collaborate closely with OEM clients to customize existing products towards their specific liquid handling needs or assist them in the development of tailor-made products according to provided specifications.

Peristaltic Pumps

Peristaltic pumps also referred to as hose or tube pumps operate using positive displacement. Fluid is fed through the tubing by rollers that rotate squeezing the tube against the pump housing.

As the roller moves over and past a point on the tubing, it expands to allow more fluid to enter. During operation, at least one roller is used to close the tube, therefore the need for extra valves is eliminated.

Peristaltic pumps are ideal for use with corrosive and viscous fluids, as the only part of the pump to come into contact with the fluid is the tubing. Depending on the model, the tubing or the head can be easily replaced while the pump itself is maintenance-free.

Peristaltic Pumps Characteristics and Benefits

Since 2019, Thomas utilizes flexible and high quality peristaltic pumpsmanufactured byOina; one of our brands. This increases our peristaltic pumps range and thepossibilities to provide solutions to demanding applications significantly. Thomas now features pumps with flow rates ranging from smaller than 0.1 up to 1,600 ml per minute. Various tube materials from silicone over medical grade tubing to FKM tubing are available depending on their compatibility with the media.

Peristaltic pumps are ideal for applications requiring minimal cross-contamination (carry-over). The only part of the pump to come into contact with the fluid is the tubing. The ease of replacing the tubing or cassette is a smooth process and ensures high process stability.

How Peristaltic Pumps Compare to Other Technologies?

Whenever viscous fluids or liquids need to be transferred, peristaltic pumps are a great solution as they do not incorporate valves.

Many medical devices, analytical instruments and bioprocessing equipment rely on peristaltic pumps, as avoidance of cross-contamination is key to process stability.

Examples of such equipment include bioreactors, cell harvesters or dialysis machines that incorporate peristaltic pumps for handling fluids.

By selecting the appropriate tubing, you can achieve high particle tolerance. A challenge for peristaltic pumps remains to provide chemical resistance over a long period of time without changing tubes. In terms of higher pressure or chemical resistance in combination with long maintenance-free lifecycles, diaphragm pumps offer better characteristics.

Diaphragm Pumps

In liquid diaphragm pumps, a flexible diaphragm is moved through the action of an eccentric on the motor shaft. On the down stroke, the medium is drawn into the pump chamber and expelled on the upstroke. Internal valves mounted within the pump head function as check valves and control the direction of flow.

Thomas is one of the only manufacturers of dedicated liquid diaphragm pumps. Unlike gases, liquids cannot be compressed and therefore create high forces on the pump components and induce pulsation. This leads to pump designs with smaller diaphragm strokes, stiffer diaphragm materials and more robust bearings compared to air pumps.

Liquid Diaphragm Pumps Characteristics and Benefits

The pumps range from 0.2 to 1.8 liters per minute and operate in pressures up to 6 bar. Twin head configurations can be offered for high volume requirements. The Thomas range features an extensive range of brushed and brushless DC motors. Depending on the type of liquid, you can choose pump components in the most suitable material, such as EPDM, FKM, PTFE or FFKM.

How Liquid Linear Pumps Compare to Other Technologies?

Liquid diaphragm pumps show high resistance to pressure combined with continuous runtimes of 10,000 hours and more. Utilizing an optimal flow rate to size ratio, liquid diaphragm pumps are the best solution for many OEM applications.

Compared with peristaltic technology, diaphragm pumps create higher pulsation due to the reciprocating pump principle. They stand out due to their superior long-term compatibility with aggressive media and unprecedented service-free lifetime.

Liquid Linear Pumps

Linear or vibrating armature pumps utilize an electromagnetic drive to apply force to a diaphragm positively displacing liquid. The alternating current reverses the magnetic field induced around a magnetized rod.

Liquid Linear Pumps Characteristics and Benefits

Thomas features linear pumps with flow rates up to 300 ml per minute and can be equipped with AC and DC motors.

Linear armature pumps are quiet and efficient. With fewer wearing parts than equivalent reciprocating pump technologies, linear pumps are regarded as long life and low maintenance devices. Their hydraulic performance is limited to the strength of the induced magnetic field, making them suitable for low differential pressure applications. These applications include delivery of methanol in fuel cells as well as constantly dispensing detergent in cleaning devices.

How Liquid Linear Pumps Compare to Other Technologies?

Linear pumps are a cost-effective solution. Compared with diaphragm or peristaltic technology, they do not handle the pulsation and pressure as well. In addition, linear pumps are not dry-running and are less suited for high pressure applications. 

If you're looking for a pump that provides long lifetime and emits the lowest sound levels in less demanding applications, linear pumps should be your choice. They are great for low-pressure requirements due to their compact size and hermetical leak tightness.

Tricontinent Precision Pumps

In addition to the Thomas brand, Gardner Denver also offers precision liquid handling equipment by Tricontinent. Tricontinent is a leading manufacturer of precision syringe pumps. They set the bar for precision and accuracy and offer a unique combination of low flow and low pulsation.

Moreover air displacement pumps are another high precision pump technology offered by Tricontinent. They function like electronic hand pipettes by aspiring a medium from one vessel and dispensing it into another vessel.

Liquid Pump Applications

Fluids That Can Be Pumped with Liquid Pumps from Thomas

Modular compact design combined with long-life durability and operating effectiveness makes Thomas liquid pumps the primary choice for handling any liquid. Our pumps seamlessly distribute even aggressive, abrasive and viscous liquids, as well as fluids with particles.   

They are versatile and suitable for a broad range of applications and find use in handling of water, food, blood, pharmaceuticals or ultrapure fluids. They can handle many chemical fluids, such as detergents, reagents, or inks.

As you can see, Thomas provides an ample selection of liquid pump models and platforms that address the needs of medical, cleaning & disinfection, environmental as well as printing industries. Below you will find just an excerpt of applications for your consideration.

In-Vitro Diagnostics

Thomas is a leading provider of miniature liquid pumps that are used to add reagents to sample fluid, remove the residue liquid and cleaning processes. Our highly integrated small pumps are characterized by robust performance and are the first choice for OEM Diagnostic equipment device manufacturers.

Diagnostic equipment (IVD) such as hematology analyzers or immunology analyzers require liquid diaphragm pumps for cleaning the sample needles. These pumps need to operate with high pressure levels. Also vacuum pump duties are common, for example when aspiration of residue liquids is needed.

Condensate Removal

Gas coolers and various condensate collecting vessels require a pump that continuously discharges gathered condensate. Liquid pumps - peristaltic pumps in particular - are the perfect fit for condensate removal, thanks to their advantages. They can operate in dirty environments and transport fluids that contain particulates. On top of that, peristaltic pumps are self-priming and dry-running.


Liquid pumps are used in kidney dialysis systems to dispense process fluids as well as deaerate the dialysate. You can lean on Thomas peristaltic technology that guarantees smooth and gentle transfer of media operates with low pulsation and is self-priming, making it the best choice.

Washer / Disinfector

Liquid pumps are used in diverse washers and disinfectors to dose disinfectant into the washing chamber. Thomas peristaltic pumps are compact in design and can be easily fitted even into small units. Because they do not have valves, their robustness against crystallization comes to the frontline. Our pumps are easy to maintain, and with a selection of the right tubing provides resistance to detergents. 

Industrial Dishwasher

Liquid pumps are a necessary part for all dishwashers, especially industrial ones. Similarly to washers and disinfectors, the best choice is peristaltic technology, due to its construction and design, chemical compatibility and accurate dosing.

Floor Cleaning

A liquid pump is used to dose detergent into the cleaning fluid for multiple floor cleaning devices. Here the most suitable is the Thomas linear liquid pump which provides the most accurate dosing, with the possibility to dosing detergent by a fraction of μl upon a single stroke. It's also cost-effective and built from chemically resistant materials.


In terms of printing, Thomas diaphragm liquid pumps are the flagship solution for each type of printing application. Our membrane pumps are the optimum choice for inkjet printing, continuous printing, CIJ – Marking & Coding applications as well as Drop-on-Demand Inkjet Systems. Our engineering knowledge allowed us to create a pump that implements continuous and smooth liquid flow with minimized pulses into a compact and fully flexible design that can be scaled and optimized for any requirements.

For example digital inkjet printers use Thomas liquid diaphragm pumps for ink handling due to their high efficiency. Digital inkjet printer manufacturers rely on Thomas liquid diaphragm pumps because of their chemical resistance against aggressive inks. Another important feature is their ability to gently move inks for up to 2 years without maintenance.